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// SPDX-License-Identifier: GPL-2.0
/* Send one TCPv4 GSO packet encapsulated in a stack of NSH headers,
* through a packet socket with PACKET_VNET_HDR.
*
* Usage: nsh_gso <ifname> <number of NSH headers>
*
* The packet is made of 4 segments. The send() result is not checked:
* the caller looks at the device counters.
*/
#include <arpa/inet.h>
#include <errno.h>
#include <error.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/virtio_net.h>
#include <net/if.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#ifndef ETH_P_NSH
#define ETH_P_NSH 0x894F
#endif
#define NSH_HLEN 8 /* base header + service path header */
#define NSH_MD_TYPE2 2 /* no mandatory context header */
#define NSH_NP_IPV4 1
#define NSH_NP_NSH 4
#define GSO_SIZE 500
#define NR_SEGS 4
struct nsh_base {
__be16 ver_flags_ttl_len;
__u8 mdtype;
__u8 np;
__be32 path_hdr;
};
int main(int argc, char **argv)
{
unsigned int depth, hlen, len, i;
struct sockaddr_ll addr = {};
struct virtio_net_hdr *vnet;
struct nsh_base *nsh;
struct ethhdr *eth;
struct tcphdr *tcp;
int fd, one = 1;
struct iphdr *ip;
char *buf;
if (argc != 3)
error(1, 0, "usage: %s <ifname> <depth>", argv[0]);
depth = strtoul(argv[2], NULL, 0);
hlen = sizeof(*eth) + depth * NSH_HLEN + sizeof(*ip) + sizeof(*tcp);
if (!depth || hlen > UINT16_MAX)
error(1, 0, "invalid depth %u", depth);
len = sizeof(*vnet) + hlen + NR_SEGS * GSO_SIZE;
buf = calloc(1, len);
if (!buf)
error(1, errno, "calloc");
vnet = (void *)buf;
vnet->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
vnet->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
vnet->hdr_len = hlen;
vnet->gso_size = GSO_SIZE;
vnet->csum_start = hlen - sizeof(*tcp);
vnet->csum_offset = __builtin_offsetof(struct tcphdr, check);
eth = (void *)(vnet + 1);
memset(eth->h_dest, 0xff, ETH_ALEN);
eth->h_source[0] = 0x02;
eth->h_proto = htons(ETH_P_NSH);
nsh = (void *)(eth + 1);
for (i = 0; i < depth; i++, nsh++) {
/* version 0, ttl 63, length in 4 byte words */
nsh->ver_flags_ttl_len = htons(63 << 6 | NSH_HLEN / 4);
nsh->mdtype = NSH_MD_TYPE2;
nsh->np = i == depth - 1 ? NSH_NP_IPV4 : NSH_NP_NSH;
nsh->path_hdr = htonl(1 << 8 | 255);
}
ip = (void *)nsh;
ip->version = 4;
ip->ihl = 5;
ip->ttl = 64;
ip->protocol = IPPROTO_TCP;
ip->saddr = htonl(0xc0000201); /* 192.0.2.1 */
ip->daddr = htonl(0xc0000202); /* 192.0.2.2 */
tcp = (void *)(ip + 1);
tcp->source = htons(1234);
tcp->dest = htons(5678);
tcp->doff = 5;
tcp->ack = 1;
fd = socket(AF_PACKET, SOCK_RAW, 0);
if (fd < 0)
error(1, errno, "socket");
if (setsockopt(fd, SOL_PACKET, PACKET_VNET_HDR, &one, sizeof(one)))
error(1, errno, "setsockopt PACKET_VNET_HDR");
addr.sll_family = AF_PACKET;
addr.sll_protocol = htons(ETH_P_NSH);
addr.sll_ifindex = if_nametoindex(argv[1]);
if (!addr.sll_ifindex)
error(1, errno, "if_nametoindex %s", argv[1]);
/* A packet dropped at segmentation time is reported as an error,
* this is expected for deep stacks.
*/
sendto(fd, buf, len, 0, (void *)&addr, sizeof(addr));
close(fd);
free(buf);
return 0;
}
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